Cut-out gear for steam turbines



J. P. ANDERSON.

CUT-OUT GEAR FOR STEAM TURBINES.

APPLICATION FILED SEPT. 30, ms.

1,435,683. Patented. Nov. 14, 11922.

A. FTTO/P/VfYS.

platform or deck should Fatented l lov. l4,

W its JOHN PUNTON ANDERSON, OF GBEENOCK, BUILDING & ENGINEERING COMPANY SCOTLAND, ASSIGNOR TO SGOTTS SHIT"- LIMITED, OF GREENOCK, SCOTLAND.

CUT-OUT GEAR FOR STEAM TURBINES.

Application filed September 30, 1919. Serial No. 327,461.

To all whom it may concern:

Be it known that 1, JOHN 1)UNTONQA:N" nnRsoN, l7 Ardgowan Street, Greenock, Scotland, a subject of the King of Great Britain, have invented a certain new and useful Improved Cut-Out Gear for Steam Turbines, of which the following is a specification.

This invention relates to steam turbines and its object is to. provide an improved automatically acting cut-out gear which will, in certain emergencies, shut the steam off the turbines.

The gear is characterized by an actuating valve which depends, for its action, upon the oil pressure in the forced lubrication system, this actuation valve controlling a self acting emergency valve capable of shutting off the steam supply to the turbines.

The actuating valve can be put in operation by- (l) The action of the turbine governors,

should the turbine revolutions exceed a pre determined limit as the' result of the breakage of a shaft, the loss of a propeller, the stripping of pinion-or gear wheel teeth, or "other cause; or

(2) By the failure of the forced lubrication system.

(3) If so desired, provision may also be made whereby it can be put in action by the operation of a lever control at the starting it be necessary to stop in an emergency.

In order that the invention may understood 1 have hereunto appcnded'an eX- planatory drawing which shows diagrammatically a suitable construction and arrangement or the cut-out gear.

Referring to the drawing:

The steam emergency valve a, which is of the seltclosing type, is arranged at the boiler side of the regulating valves and has a valve 7) on the spindle b which latter also carries a piston 0 at its upper end the area of the piston being in'excess of that of the valve so that the latter cannot open under pressure of steam entering at a until the pressures atiboth sides of the piston c are substantially equalized, this being. done in a few moments by the passage of steam he clearly througha small by-pass port (Z the outlet of which is controlled by means of a pin valve 6. When the pressures are substantially the valve 6 opens to the extent space 0 at the upper side of the piston c i to a point of lower pressure so that the unbalanced pressure on the underside will at once raise the piston and close the valve in well known manner.

The actuating valve 9, which may be located in proximity to the emergency valve, preferably consists of a sleeve valve in which when in the upper position, closes the connection from the space 0 of the emergency valve and, when in the lower position, opens the connection by valve passage 7L1 and valve groove k to the pipe w leading to the hot well tank. Secured to the lower end of the spindle of the valve 7b is a heavy ram is which works in a separate cylinder Z to which oil from the forced lubrication system is admitted by means of the pipe Z and the actuating valve 7a is normally retained in its upper position by the pressure of the oil acting on the underside of the ram. The space at the upper side of the ram is con-- nected with the oil drain'tank by means of the pipe m. The area and weight of the ram are so proportioned that it continues to termined limit, say, for. instance, that corresponding to a head of 2 feet.

llhenever the oil pressure, from any cause, is reduced below this limit the ram'immediately falls and moves the actuating valve h to its lower position thereby opening comuuinication between. the space c and the hot well tank thus causing the emergency valve (5 to close automaticallyand shut off the steam into the turbines.

The oil supply for the cylinder Z comes from the forced. lubrication system direct or from the gravity tank a and pipes at, :0 and passes through the valves 5, t co11 trolled by the governors g, 9 ofl'he high pressure and low pressure turbines and thence through pipe 511 and switch cock 7' to or operated from the deck or elsewhere. The discharge from the cock 1* passes by the pipe m to the oil drain tank.

The governors of the low pressure and high pressure turbines are shown as of the eccentric ring type but, of course, they may be oi other known type. o, '1), are detent levers which normally support the valve spindles y, of the governor valves [5, 75 the spindles having, at their upper ends, weights u, PI/1'. m are oil drain pipes. The detent levers n, w, are suitably 'ti'ilcrui'ned and are held in position. by springs The upper ends of the valve spindles y, 3 serve as valves and, when in the position shown on the drawings, they close the lower ends of the valve cylinders 72, p whilst, when they are moved downwards by the weights a, M on the disengagement of the detent levers o, 12 they open these cylinders and allow oil to drain away from the pi pes a 00 to the drain pipes m The action of the cut-out gear is as follows a) Turbine governor action: Should the rate of revolution of the turbine having, say, the governor g exceed a predetermined limit then the eccentric ring flies out radially and trips the detent o whereupon the spindle 3 falls, under the action of the weight a, and causes the valve 23 to shut off the pressure oil, whereupon the oil from the cylinder Z will pass away by pipes Z 00 and m and the ram 76 will fall and move the valve /L to open the exhaust from space 0 and cause the emergency valve Z) to act.

It will be seen "from the drawing that a similar action will take place in connection with the turbine governor Q should it op crate.

(b) By failure of the forced lubrication system: As previously mentioned the area and weight of the actuating ram 79 are proportioned so that it is supported by any pressure in excess of a predetermined limit, say, that corresponding to a head of 2 feet, consequently, the ram will operate to close the emergency valve when the gravity tank is empty and the oil in the pipe 00 leading from it has fallen to a level less than 2 feet above the height of the cylinder Z.-

(c) By the operation oi? the lever control 5:. The cock 1' is made, as shown, with a right-angle port in the plug so that the movement of the lever, as indicated by the dotted lines, will shut ofl? the pressure oil and, at the same time, connect the pipe Z with the drain pipe 077. thereby emptying the cylinder Z and allowing the ram 70 to move and cause the emergency valve to act.

The arrangement I have shown on the drawings is merely by way of example. It is obvious it can be readily modified or al- -t ered without departing from the invention;

are "instance, a light piston ma replace the ram 7: in which case the piston would be retained in its upper position by the oil pressure against the action of a spring or of balance weights which may be adjusted to balance the oil pressure at any predetermined limit.

Having now fully described my invention what I claim and desire to secure by Letters Patent is 1. A cut out gear for steam turbines with. forced lubrication system, comprising an emergency valve for cutting oil the steam supply to the turbines, an actuating valve for controlling the emergency valve, a cylinder, a piston therein connected with said actuating valve, means establishing connection between one end of said cylinder and the forced lubrication system and manually controlled means for operating said actuating valve, at will, by effecting a reduction of the oil pressurein the lubrication system.

2. A cut out. gear for steam turbines with forced lubrication system, comprising an emergency valve for cutting off the steam supply to the turbines, an actuating valve for controlling the emergency valve, a cylinder, a piston therein connected with said actuating valve, means establishing connection between one end of said cylinder and the forced lubrication system and means automatically actuated by the turbine governor to effect a reduction of the oil pressure in the lubrication system in the case of the turbine exceeding a predetermined speed.

3. A cut out gear for steam turbines with torced lubrication system, comprising an emergency valve for cutting oil the steam supply to the turbines, an actuating valve for controlling the emergency valve, a cylinder, a piston therein connected with said actuating valve, means establishing connection between one end of said cylinder and the forced lubrication system and means for automatically operating said valve from the turbine governor when the turbine exceeds a predetermined speed.

4. A cut out gear for steam turbines with forced lubrication system, comprising an emergency valve for cutting oil the steam supply to the turbines, an actuating valve for controlling the emergency valve, a cylinder, a piston therein connected with said actuating valve, means establishing connection between one end. of said cylinder and the forced lubrication system, means for automatically actuating said valve from the turbine governor when the turbine exceeds a predetermined speed, and manually controlled means for operating said valve, at will, by efl'ecting a reduction of oil pressure in the lubrication system.

5. A cut out gear for steam turbines with forced lubrication system, comprising an emergency valve for cutting cit the steam V supply to the turbines, an actuating valve for controlling the emergency valve, a cylinder, a piston therein connected with said actuatingvalve, means establishing connec- .tion between one end of said cylinder and the forced lubrication system and hand operated means whereby a reduction of pressure in the lubrication system can be effected in case of emergency to operate the valve and cut off the steam supply to the turbines.

6; A cut out gear for steam turbines with forced lubrication system, comprising an emergency valve for cutting off the steam supply to the turbines, an actuating valve for controlling the emergency valve,a cylinder, a piston therein connected with said actuating valve, means establishing connection. between one end of said cylinder and the forced lubrication system, means whereby a reduction of oil pressure can be effected by governor action should theturbines ex- 'ceed a' certain speed of revolution and hand operated means-for effecting a reduction of oil pressure in the lubrication system in cases of emergency.

7 A cut out gear for steam turbines with forced lubrication system comprising an emergency valve, a cylinder having an ex haust port, a piston in said cylinder operatively connected with the emergency valve, means for admitting steam to both sides of said piston, a casing having an exhaust port therein, means connecting said casing with the exhaust port of said cylinder, a sleeve valve in said casing, a second cylinder, a piston therein operatively connected with said sleeve valve, and means connecting one end of said second cylinder with the forced lubrication system.

8. A cut out gear for steam turbines with forced lubrication system comprising an emergency valve, a cylinder having an exhaust port, a piston in said cylinder operatively connected with the emergency valve, means for admitting steam to both sides of said piston, an actuating valve adapted to control said exhaust port, a second cylinder, a piston in said second cylinder operatively connected with the actuating valve, pipes communicating with said second cylinder and the supply and return of the forced lubrication. system and a manually controlled valve in connection with said pipes adapted to place one end of said second cylinder in communication with the supply or return of the forced lubrication system.

9. A cut out gear for steam turbines with forced lubrication system comprising an emergency valve, a cylinder having an exhaust port, a piston in said cylinder operatively connected with the emergency valve, means for admitting steam to both sides of said piston, an actuating valve adapted to control said exhaust port, a second cylinder, a piston in said second cylinder operativel connected with the actuating valve, means connecting one end'of said second cylinder with the supply of the forced lubrication system and a governor in connection with the turbine adapted to break the connection between said second cylinder and the supply of the forced lubrication system and to place said cylinder in communication with the return of the forced lubrication system.

10. A cut out gear for steam turbines with forced lubrication system comprising an emergency valve, a cylinder having an exhaust port, a piston in said cylinder operatively connected with the emergency valve, means for admitting steam to both sides of said piston, an actuating valve adapted to control said exhaust port, a second cylinder, a piston in said second cylinder operatively connected with the actuating valve, means connecting one end of said second cylinder with the supply of the forced lubrication system, a governor in connection with the turbine and a gravity controlled valve in connection with said governor adapted to break the connection between said second cylinder and the supply of the forced lubrication system and to place said cylinder in communication with the return of the forced lubrication system,

In testimony whereof I affix my signature in presence of two witnesses.

JOHN PUNTON ANDERSON.

Witnesses:

H. D. FITZPATRIOK, MARY GREEN. 

